Tax reporting of gain/loss on covered calls?

I sold covered calls on a stock I own (short-term holding period) and identified them as a straddle with the stock I own. They are not qualified. (I sold them less than 30 days before the expiration.) They expired worthless. I know I have a short term gain, but how/where do I report it? A single line on Schedule D like I would for a stock or do I have to use form 6781? If I have to use 6781, what do I put on what lines? I've never used that form before and don't really understand it.

Second situation: A few days after the previous expiration, I wrote new options against the same stock (and identified them as a straddle). I later bought the options back for a loss. I didn't have any more options transactions for 3 months, so this shouldn't be a wash sale. Because this is an "identified straddle", I think I add the loss to the basis of the stock. What, if anything, do I report on which forms? Again, if it's 6781, please help me understand what I put on which lines of 6781.